Active Stylus With Surface-Modification Materials

ABSTRACT

In one embodiment, a stylus has one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for transmitting signals wirelessly to a device through a touch-sensor of the device. The stylus also has an electronic circuit operable to provide an input that changes a property of one or more materials located on the body of the stylus or on the stylus tip.

RELATED APPLICATION

This application claims the benefit, under 35 U.S.C. §119(e), of U.S.Provisional Patent Application No. 61/553,114, filed 28 Oct. 2011, whichis incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to active styluses.

BACKGROUND

A touch sensor may detect the presence and location of a touch or theproximity of an object (such as a user's finger or a stylus) within atouch-sensitive area of the touch sensor overlaid on a display screen,for example. In a touch-sensitive-display application, the touch sensormay enable a user to interact directly with what is displayed on thescreen, rather than indirectly with a mouse or touch pad. A touch sensormay be attached to or provided as part of a desktop computer, laptopcomputer, tablet computer, personal digital assistant (PDA), smartphone,satellite navigation device, portable media player, portable gameconsole, kiosk computer, point-of-sale device, or other suitable device.A control panel on a household or other appliance may include a touchsensor.

There are a number of different types of touch sensors, such as, forexample, resistive touch screens, surface acoustic wave touch screens,and capacitive touch screens. Herein, reference to a touch sensor mayencompass a touch screen, and vice versa, where appropriate. When anobject touches or comes within proximity of the surface of thecapacitive touch screen, a change in capacitance may occur within thetouch screen at the location of the touch or proximity. A touch-sensorcontroller may process the change in capacitance to determine itsposition on the touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor with an example touch-sensorcontroller.

FIG. 2 illustrates an example active stylus exterior.

FIG. 3 illustrates an example active stylus interior.

FIG. 4 illustrates an example active stylus with touch sensor device.

FIG. 5 illustrates an example active stylus with surface-modificationmaterials.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates an example touch sensor 10 with an exampletouch-sensor controller 12. Touch sensor 10 and touch-sensor controller12 may detect the presence and location of a touch or the proximity ofan object within a touch-sensitive area of touch sensor 10. Herein,reference to a touch sensor may encompass both the touch sensor and itstouch-sensor controller, where appropriate. Similarly, reference to atouch-sensor controller may encompass both the touch-sensor controllerand its touch sensor, where appropriate. Touch sensor 10 may include oneor more touch-sensitive areas, where appropriate. Touch sensor 10 mayinclude an array of drive and sense electrodes (or an array ofelectrodes of a single type) disposed on one or more substrates, whichmay be made of a dielectric material. Herein, reference to a touchsensor may encompass both the electrodes of the touch sensor and thesubstrate(s) that they are disposed on, where appropriate.Alternatively, where appropriate, reference to a touch sensor mayencompass the electrodes of the touch sensor, but not the substrate(s)that they are disposed on

An electrode (whether a ground electrode, guard electrode, driveelectrode, or sense electrode) may be an area of conductive materialforming a shape, such as for example a disc, square, rectangle, thinline, other suitable shape, or suitable combination of these. One ormore cuts in one or more layers of conductive material may (at least inpart) create the shape of an electrode, and the area of the shape may(at least in part) be bounded by those cuts. In particular embodiments,the conductive material of an electrode may occupy approximately 100% ofthe area of its shape. As an example and not by way of limitation, anelectrode may be made of indium tin oxide (ITO) and the ITO of theelectrode may occupy approximately 100% of the area of its shape(sometimes referred to as a 100% fill), where appropriate. In particularembodiments, the conductive material of an electrode may occupysubstantially less than 100% of the area of its shape. As an example andnot by way of limitation, an electrode may be made of fine lines ofmetal or other conductive material (FLM), such as for example copper,silver, or a copper- or silver-based material, and the fine lines ofconductive material may occupy approximately 5% of the area of its shapein a hatched, mesh, or other suitable pattern. Herein, reference to FLMencompasses such material, where appropriate. Although this disclosuredescribes or illustrates particular electrodes made of particularconductive material forming particular shapes with particular fillpercentages having particular patterns, this disclosure contemplates anysuitable electrodes made of any suitable conductive material forming anysuitable shapes with any suitable fill percentages having any suitablepatterns.

Where appropriate, the shapes of the electrodes (or other elements) of atouch sensor may constitute in whole or in part one or moremacro-features of the touch sensor. One or more characteristics of theimplementation of those shapes (such as, for example, the conductivematerials, fills, or patterns within the shapes) may constitute in wholeor in part one or more micro-features of the touch sensor. One or moremacro-features of a touch sensor may determine one or morecharacteristics of its functionality, and one or more micro-features ofthe touch sensor may determine one or more optical features of the touchsensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates)and the conductive material forming the drive or sense electrodes oftouch sensor 10. As an example and not by way of limitation, themechanical stack may include a first layer of optically clear adhesive(OCA) beneath a cover panel. The cover panel may be clear and made of aresilient material suitable for repeated touching, such as for exampleglass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA may be disposed between the cover paneland the substrate with the conductive material forming the drive orsense electrodes. The mechanical stack may also include a second layerof OCA and a dielectric layer (which may be made of PET or anothersuitable material, similar to the substrate with the conductive materialforming the drive or sense electrodes). As an alternative, whereappropriate, a thin coating of a dielectric material may be appliedinstead of the second layer of OCA and the dielectric layer. The secondlayer of OCA may be disposed between the substrate with the conductivematerial making up the drive or sense electrodes and the dielectriclayer, and the dielectric layer may be disposed between the second layerof OCA and an air gap to a display of a device including touch sensor 10and touch-sensor controller 12. As an example only and not by way oflimitation, the cover panel may have a thickness of approximately 1 mm;the first layer of OCA may have a thickness of approximately 0.05 mm;the substrate with the conductive material forming the drive or senseelectrodes may have a thickness of approximately 0.05 mm; the secondlayer of OCA may have a thickness of approximately 0.05 mm; and thedielectric layer may have a thickness of approximately 0.05 mm. Althoughthis disclosure describes a particular mechanical stack with aparticular number of particular layers made of particular materials andhaving particular thicknesses, this disclosure contemplates any suitablemechanical stack with any suitable number of any suitable layers made ofany suitable materials and having any suitable thicknesses. As anexample and not by way of limitation, in particular embodiments, a layerof adhesive or dielectric may replace the dielectric layer, second layerof OCA, and air gap described above, with there being no air gap to thedisplay.

One or more portions of the substrate of touch sensor 10 may be made ofpolyethylene terephthalate (PET) or another suitable material. Thisdisclosure contemplates any suitable substrate with any suitableportions made of any suitable material. In particular embodiments, thedrive or sense electrodes in touch sensor 10 may be made of ITO in wholeor in part. In particular embodiments, the drive or sense electrodes intouch sensor 10 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, one or moreportions of the conductive material may be copper or copper-based andhave a thickness of approximately 5 μm or less and a width ofapproximately 10 μm or less. As another example, one or more portions ofthe conductive material may be silver or silver-based and similarly havea thickness of approximately 5 μm or less and a width of approximately10 μm or less. This disclosure contemplates any suitable electrodes madeof any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 may include an arrayof drive and sense electrodes forming an array of capacitive nodes. Adrive electrode and a sense electrode may form a capacitive node. Thedrive and sense electrodes forming the capacitive node may come neareach other, but not make electrical contact with each other. Instead,the drive and sense electrodes may be capacitively coupled to each otheracross a space between them. A pulsed or alternating voltage applied tothe drive electrode (by touch-sensor controller 12) may induce a chargeon the sense electrode, and the amount of charge induced may besusceptible to external influence (such as a touch or the proximity ofan object). When an object touches or comes within proximity of thecapacitive node, a change in capacitance may occur at the capacitivenode and touch-sensor controller 12 may measure the change incapacitance. By measuring changes in capacitance throughout the array,touch-sensor controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include anarray of electrodes of a single type that may each form a capacitivenode. When an object touches or comes within proximity of the capacitivenode, a change in self-capacitance may occur at the capacitive node andcontroller 12 may measure the change in capacitance, for example, as achange in the amount of charge needed to raise the voltage at thecapacitive node by a pre-determined amount. As with a mutual-capacitanceimplementation, by measuring changes in capacitance throughout thearray, controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10. Thisdisclosure contemplates any suitable form of capacitive touch sensing,where appropriate.

In particular embodiments, one or more drive electrodes may togetherform a drive line running horizontally or vertically or in any suitableorientation. Similarly, one or more sense electrodes may together form asense line running horizontally or vertically or in any suitableorientation. In particular embodiments, drive lines may runsubstantially perpendicular to sense lines. Herein, reference to a driveline may encompass one or more drive electrodes making up the driveline, and vice versa, where appropriate. Similarly, reference to a senseline may encompass one or more sense electrodes making up the senseline, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in apattern on one side of a single substrate. In such a configuration, apair of drive and sense electrodes capacitively coupled to each otheracross a space between them may form a capacitive node. For aself-capacitance implementation, electrodes of only a single type may bedisposed in a pattern on a single substrate. In addition or as analternative to having drive and sense electrodes disposed in a patternon one side of a single substrate, touch sensor 10 may have driveelectrodes disposed in a pattern on one side of a substrate and senseelectrodes disposed in a pattern on another side of the substrate.Moreover, touch sensor 10 may have drive electrodes disposed in apattern on one side of one substrate and sense electrodes disposed in apattern on one side of another substrate. In such configurations, anintersection of a drive electrode and a sense electrode may form acapacitive node. Such an intersection may be a location where the driveelectrode and the sense electrode “cross” or come nearest each other intheir respective planes. The drive and sense electrodes do not makeelectrical contact with each other—instead they are capacitively coupledto each other across a dielectric at the intersection. Although thisdisclosure describes particular configurations of particular electrodesforming particular nodes, this disclosure contemplates any suitableconfiguration of any suitable electrodes forming any suitable nodes.Moreover, this disclosure contemplates any suitable electrodes disposedon any suitable number of any suitable substrates in any suitablepatterns.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 may indicate a touch or proximity input at the positionof the capacitive node. Touch-sensor controller 12 may detect andprocess the change in capacitance to determine the presence and locationof the touch or proximity input. Touch-sensor controller 12 may thencommunicate information about the touch or proximity input to one ormore other components (such one or more central processing units (CPUs))of a device that includes touch sensor 10 and touch-sensor controller12, which may respond to the touch or proximity input by initiating afunction of the device (or an application running on the device).Although this disclosure describes a particular touch-sensor controllerhaving particular functionality with respect to a particular device anda particular touch sensor, this disclosure contemplates any suitabletouch-sensor controller having any suitable functionality with respectto any suitable device and any suitable touch sensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices (PLDs) or programmable logic arrays (PLAs),application-specific ICs (ASICs). In particular embodiments,touch-sensor controller 12 comprises analog circuitry, digital logic,and digital non-volatile memory. In particular embodiments, touch-sensorcontroller 12 is disposed on a flexible printed circuit (FPC) bonded tothe substrate of touch sensor 10, as described below. The FPC may beactive or passive, where appropriate. In particular embodiments multipletouch-sensor controllers 12 are disposed on the FPC. Touch-sensorcontroller 12 may include a processor unit, a drive unit, a sense unit,and a storage unit. The drive unit may supply drive signals to the driveelectrodes of touch sensor 10. The sense unit may sense charge at thecapacitive nodes of touch sensor 10 and provide measurement signals tothe processor unit representing capacitances at the capacitive nodes.The processor unit may control the supply of drive signals to the driveelectrodes by the drive unit and process measurement signals from thesense unit to detect and process the presence and location of a touch orproximity input within the touch-sensitive area(s) of touch sensor 10.The processor unit may also track changes in the position of a touch orproximity input within the touch-sensitive area(s) of touch sensor 10.The storage unit may store programming for execution by the processorunit, including programming for controlling the drive unit to supplydrive signals to the drive electrodes, programming for processingmeasurement signals from the sense unit, and other suitable programming,where appropriate. Although this disclosure describes a particulartouch-sensor controller having a particular implementation withparticular components, this disclosure contemplates any suitabletouch-sensor controller having any suitable implementation with anysuitable components.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 may couple the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 may extend into or around (e.g.at the edges of) the touch-sensitive area(s) of touch sensor 10.Particular tracks 14 may provide drive connections for couplingtouch-sensor controller 12 to drive electrodes of touch sensor 10,through which the drive unit of touch-sensor controller 12 may supplydrive signals to the drive electrodes. Other tracks 14 may provide senseconnections for coupling touch-sensor controller 12 to sense electrodesof touch sensor 10, through which the sense unit of touch-sensorcontroller 12 may sense charge at the capacitive nodes of touch sensor10. Tracks 14 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, the conductivematerial of tracks 14 may be copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 may be silver or silver-based and have a width ofapproximately 100 μm or less. In particular embodiments, tracks 14 maybe made of ITO in whole or in part in addition or as an alternative tofine lines of metal or other conductive material. Although thisdisclosure describes particular tracks made of particular materials withparticular widths, this disclosure contemplates any suitable tracks madeof any suitable materials with any suitable widths. In addition totracks 14, touch sensor 10 may include one or more ground linesterminating at a ground connector (which may be a connection pad 16) atan edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of thesubstrate, outside the touch-sensitive area(s) of touch sensor 10. Asdescribed above, touch-sensor controller 12 may be on an FPC. Connectionpads 16 may be made of the same material as tracks 14 and may be bondedto the FPC using an anisotropic conductive film (ACF). Connection 18 mayinclude conductive lines on the FPC coupling touch-sensor controller 12to connection pads 16, in turn coupling touch-sensor controller 12 totracks 14 and to the drive or sense electrodes of touch sensor 10. Inanother embodiment, connection pads 16 may be connected to anelectro-mechanical connector (such as a zero insertion forcewire-to-board connector); in this embodiment, connection 18 may not needto include an FPC. This disclosure contemplates any suitable connection18 between touch-sensor controller 12 and touch sensor 10.

FIG. 2 illustrates an example exterior of an example active stylus 20.Active stylus 20 may include one or more components, such as buttons 30or sliders 32 and 34 integrated with an outer body 22. These externalcomponents may provide for interaction between active stylus 20 and auser or between a device and a user. As an example and not by way oflimitation, interactions may include communication between active stylus20 and a device, enabling or altering functionality of active stylus 20or a device, or providing feedback to or accepting input from one ormore users. The device may by any suitable device, such as, for exampleand without limitation, a desktop computer, laptop computer, tabletcomputer, personal digital assistant (PDA), smartphone, satellitenavigation device, portable media player, portable game console, kioskcomputer, point-of-sale device, or other suitable device. Although thisdisclosure provides specific examples of particular componentsconfigured to provide particular interactions, this disclosurecontemplates any suitable component configured to provide any suitableinteraction. Active stylus 20 may have any suitable dimensions withouter body 22 made of any suitable material or combination of materials,such as, for example and without limitation, plastic or metal. Inparticular embodiments, exterior components (e.g. 30 or 32) of activestylus 20 may interact with internal components or programming of activestylus 20 or may initiate one or more interactions with one or moredevices or other active styluses 20.

As described above, actuating one or more particular components mayinitiate an interaction between active stylus 20 and a user or betweenthe device and the user. Components of active stylus 20 may include oneor more buttons 30 or one or more sliders 32 and 34. As an example andnot by way of limitation, buttons 30 or sliders 32 and 34 may bemechanical or capacitive and may function as a roller, trackball, orwheel. As another example, one or more sliders 32 or 34 may function asa vertical slider 34 aligned along a longitudinal axis, while one ormore wheel sliders 32 may be aligned along the circumference of activestylus 20. In particular embodiments, capacitive sliders 32 and 34 orbuttons 30 may be implemented using one or more touch-sensitive areas.Touch-sensitive areas may have any suitable shape, dimensions, location,or be made from any suitable material. As an example and not by way oflimitation, sliders 32 and 34 or buttons 30 may be implemented usingareas of flexible mesh formed using lines of conductive material. Asanother example, sliders 32 and 34 or buttons 30 may be implementedusing a FPC.

Active stylus 20 may have one or more components configured to providefeedback to or accepting feedback from a user, such as, for example andwithout limitation, tactile, visual, or audio feedback. Active stylus 20may include one or more ridges or grooves 24 on its outer body 22.Ridges or grooves 24 may have any suitable dimensions, have any suitablespacing between ridges or grooves, or be located at any suitable area onouter body 22 of active stylus 20. As an example and not by way oflimitation, ridges 24 may enhance a user's grip on outer body 22 ofactive stylus 20 or provide tactile feedback to or accept tactile inputfrom a user. Active stylus 20 may include one or more audio components38 capable of transmitting and receiving audio signals. As an exampleand not by way of limitation, audio component 38 may contain amicrophone capable of recording or transmitting one or more users'voices. As another example, audio component 38 may provide an auditoryindication of a power status of active stylus 20. Active stylus 20 mayinclude one or more visual feedback components 36, such as alight-emitting diode (LED) indicator. As an example and not by way oflimitation, visual feedback component 36 may indicate a power status ofactive stylus 20 to the user.

One or more modified surface areas 40 may form one or more components onouter body 22 of active stylus 20. Properties of modified surface areas40 may be different than properties of the remaining surface of outerbody 22. As an example and not by way of limitation, modified surfacearea 40 may be modified to have a different texture, temperature, orelectromagnetic characteristic relative to the surface properties of theremainder of outer body 22. Modified surface area 40 may be capable ofdynamically altering its properties, for example by using hapticinterfaces or rendering techniques. A user may interact with modifiedsurface area 40 to provide any suitable functionally. For example andnot by way of limitation, dragging a finger across modified surface area40 may initiate an interaction, such as data transfer, between activestylus 20 and a device.

One or more components of active stylus 20 may be configured tocommunicate data between active stylus 20 and the device. For example,active stylus 20 may include one or more tips 26 or nibs. Tip 26 mayinclude one or more electrodes configured to communicate data betweenactive stylus 20 and one or more devices or other active styluses. Tip26 may be made of any suitable material, such as a conductive material,and have any suitable dimensions, such as, for example, a diameter of 1mm or less at its terminal end. Active stylus 20 may include one or moreports 28 located at any suitable location on outer body 22 of activestylus 20. Port 28 may be configured to transfer signals or informationbetween active stylus 20 and one or more devices or power sources. Port28 may transfer signals or information by any suitable technology, suchas, for example, by universal serial bus (USB) or Ethernet connections.Although this disclosure describes and illustrates a particularconfiguration of particular components with particular locations,dimensions, composition and functionality, this disclosure contemplatesany suitable configuration of suitable components with any suitablelocations, dimensions, composition, and functionality with respect toactive stylus 20.

FIG. 3 illustrates an example internal components of example activestylus 20. Active stylus 20 may include one or more internal components,such as a controller 50, sensors 42, memory 44, or power source 48. Inparticular embodiments, one or more internal components may beconfigured to provide for interaction between active stylus 20 and auser or between a device and a user. In other particular embodiments,one or more internal components, in conjunction with one or moreexternal components described above, may be configured to provideinteraction between active stylus 20 and a user or between a device anda user. As an example and not by way of limitation, interactions mayinclude communication between active stylus 20 and a device, enabling oraltering functionality of active stylus 20 or a device, or providingfeedback to or accepting input from one or more users.

Controller 50 may be a microcontroller or any other type of processorsuitable for controlling the operation of active stylus 20. Controller50 may be one or more ICs—such as, for example, general-purposemicroprocessors, microcontrollers, PLDs, PLAs, or ASICs. Controller 50may include a processor unit, a drive unit, a sense unit, and a storageunit. The drive unit may supply signals to electrodes of tip 26 throughcenter shaft 41. The drive unit may also supply signals to control ordrive sensors 42 or one or more external components of active stylus 20.The sense unit may sense signals received by electrodes of tip 26through center shaft 41 and provide measurement signals to the processorunit representing input from a device. The sense unit may also sensesignals generated by sensors 42 or one or more external components andprovide measurement signals to the processor unit representing inputfrom a user. The processor unit may control the supply of signals to theelectrodes of tip 26 and process measurement signals from the sense unitto detect and process input from the device. The processor unit may alsoprocess measurement signals from sensors 42 or one or more externalcomponents. The storage unit may store programming for execution by theprocessor unit, including programming for controlling the drive unit tosupply signals to the electrodes of tip 26, programming for processingmeasurement signals from the sense unit corresponding to input from thedevice, programming for processing measurement signals from sensors 42or external components to initiate a pre-determined function or gestureto be performed by active stylus 20 or the device, and other suitableprogramming, where appropriate. As an example and not by way oflimitation, programming executed by controller 50 may electronicallyfilter signals received from the sense unit. Although this disclosuredescribes a particular controller 50 having a particular implementationwith particular components, this disclosure contemplates any suitablecontroller having any suitable implementation with any suitablecomponents.

In particular embodiments, active stylus 20 may include one or moresensors 42, such as touch sensors, gyroscopes, accelerometers, contactsensors, or any other type of sensor that detect or measure data aboutthe environment in which active stylus 20 operates. Sensors 42 maydetect and measure one or more characteristic of active stylus 20, suchas acceleration or movement, orientation, contact, pressure on outerbody 22, force on tip 26, vibration, or any other suitablecharacteristic of active stylus 20. As an example and not by way oflimitation, sensors 42 may be implemented mechanically, electronically,or capcatively. As described above, data detected or measured by sensors42 communicated to controller 50 may initiate a pre-determined functionor gesture to be performed by active stylus 20 or the device. Inparticular embodiments, data detected or received by sensors 42 may bestored in memory 44. Memory 44 may be any form of memory suitable forstoring data in active stylus 20. In other particular embodiments,controller 50 may access data stored in memory 44. As an example and notby way of limitation, memory 44 may store programming for execution bythe processor unit of controller 50. As another example, data measuredby sensors 42 may be processed by controller 50 and stored in memory 44.

Power source 48 may be any type of stored-energy source, includingelectrical or chemical-energy sources, suitable for powering theoperation of active stylus 20. In particular embodiments, power source48 may be charged by energy from a user or device. As an example and notby way of limitation, power source 48 may be a rechargeable battery thatmay be charged by motion induced on active stylus 20. In otherparticular embodiments, power source 48 of active stylus 20 may providepower to or receive power from the device. As an example and not by wayof limitation, power may be inductively transferred between power source48 and a power source of the device.

FIG. 4 illustrates an example active stylus 20 with an example device52. Device 52 may have a display (not shown) and a touch sensor with atouch-sensitive area 54. Device 52 display may be a liquid crystaldisplay (LCD), a LED display, a LED-backlight LCD, or other suitabledisplay and may be visible though a cover panel and substrate (and thedrive and sense electrodes of the touch sensor disposed on it) of device52. Although this disclosure describes a particular device display andparticular display types, this disclosure contemplates any suitabledevice display and any suitable display types.

Device 52 electronics may provide the functionality of device 52. Asexample and not by way of limitation, device 52 electronics may includecircuitry or other electronics for wireless communication to or fromdevice 52, execute programming on device 52, generating graphical orother user interfaces (UIs) for device 52 display to display to a user,managing power to device 52 from a battery or other power source, takingstill pictures, recording video, other suitable functionality, or anysuitable combination of these. Although this disclosure describesparticular device electronics providing particular functionality of aparticular device, this disclosure contemplates any suitable deviceelectronics providing any suitable functionality of any suitable device.

In particular embodiments, active stylus 20 and device 52 may besynchronized prior to communication of data between active stylus 20 anddevice 52. As an example and not by way of limitation, active stylus 20may be synchronized to device through a pre-determined bit sequencetransmitted by the touch sensor of device 52. As another example, activestylus 20 may be synchronized to device by processing the drive signaltransmitted by drive electrodes of the touch sensor of device 52. Activestylus 20 may interact or communicate with device 52 when active stylus20 is brought in contact with or in proximity to touch-sensitive area 54of the touch sensor of device 52. In particular embodiments, interactionbetween active stylus 20 and device 52 may be capacitive or inductive.As an example and not by way of limitation, when active stylus 20 isbrought in contact with or in the proximity of touch-sensitive area 54of device 52, signals generated by active stylus 20 may influencecapacitive nodes of touch-sensitive area of device 52 or vice versa. Asanother example, a power source of active stylus 20 may be inductivelycharged through the touch sensor of device 52, or vice versa. Althoughthis disclosure describes particular interactions and communicationsbetween active stylus 20 and device 52, this disclosure contemplates anysuitable interactions and communications through any suitable means,such as mechanical forces, current, voltage, or electromagnetic fields.

In particular embodiments, measurement signal from the sensors of activestylus 20 may initiate, provide for, or terminate interactions betweenactive stylus 20 and one or more devices 52 or one or more users, asdescribed above. Interaction between active stylus 20 and device 52 mayoccur when active stylus 20 is contacting or in proximity to device 52.As an example and not by way of limitation, a user may perform a gestureor sequence of gestures, such as shaking or inverting active stylus 20,whilst active stylus 20 is hovering above touch-sensitive area 54 ofdevice 52. Active stylus may interact with device 52 based on thegesture performed with active stylus 20 to initiate a pre-determinedfunction, such as authenticating a user associated with active stylus 20or device 52. Although this disclosure describes particular movementsproviding particular types of interactions between active stylus 20 anddevice 52, this disclosure contemplates any suitable movementinfluencing any suitable interaction in any suitable way.

In particular embodiments, a stylus may, at least partially, comprisematerials on or near the surface of its outer body that are capable ofmodifying their properties in response to one or more inputs. Suchmaterials on or near the surface of a stylus' outer body may be referredto as “surface-modification materials”. Surface-modification materialsmay change their size, shape, texture, hardness, effective coefficientof friction, brightness, color, temperature, opacity, viscosity, orother suitable characteristic in response to an electromagnetic field,an electric current, a pH level, a temperature, a radio frequency, orany other suitable input. Surface-modification materials may includeshape memory alloys, shape memory polymers, electronic or ionicelectroactive polymers (EAPs), magnetocaloric materials, thermoelectricmaterials, pH-sensitive materials, temperature-responsive materials,piezoelectrics, halochromic materials, chromogenic materials,photomechanical materials, or any other suitable material. The inputthat induces change in surface-modification materials may originate froma touch-sensitive system, such as a stylus or touch-sensitive device.For example, in response to a signal an electronic circuit in an activestylus may produce the input that induces change in surface-modificationmaterials, for example by generating or initiating the generation ofelectromagnetic signals, electrical current, or a certain temperature orpH level. The signal received by the electronic circuit may be initiatedby a user of the active stylus, for example by the press of a button.The signal received by the electronic circuit may also be initiated bysoftware or settings embodied in non-transitory computer-readable media.These settings may be set by a user of an active stylus, exist aspresets on the active stylus, or be set by individual applications orprograms associated with the active stylus. Likewise, functionalitiesassociated with altering the properties or characteristics of thesurface-modification materials may be set by a user of an active stylus,exist as presets on the active stylus, or be set by individualapplications or programs associated with the active stylus. FIG. 5illustrates an example active stylus with surface-modificationmaterials. Surface-modification materials may appear on or near thesurface of tip 26 of active stylus 20. In addition or alternatively,surface-modification materials may also appear on or near the outer body22 of active stylus 20, and may comprise one or more buttons 30, sliders32, textured surfaces 40, surface areas 56, or other suitablecomponents.

In particular embodiments, one or more buttons 30 at least partiallycomprising surface-modification materials may change their properties inorder to provide feedback to a user of active stylus 20. As an example,buttons 30 may comprise an ionic electroactive polymer contained in asuitable enclosure to maintain wetness of the polymer. When subject toan electric current created by an appropriate voltage source (forexample, approximately 1 to 10 volts) the ionic polymer may change itsviscosity, altering the force required to press the button. This mayalert that user that they are in a specific setting or are about toperform a specific function, such as deleting data. In particularembodiments, one or more buttons 30 at least partially comprisingsurface-modification materials may change their properties to alter orgenerate input to a touch-sensitive system. Using the example above,buttons 30 may navigate through menus or select menu options when usedin normal operation and exit applications when used while exposed to avoltage making button 30 stiffer or changing its size or shape. Whilethe above disclosure provides specific examples of buttons comprisingsurface-modification materials providing specific functionality, thisdisclosure contemplates any suitable surface-modification materials onany suitable component of an active stylus providing any suitablefunctionality.

In particular embodiments, one or more sliders 32 at least partiallycomprising surface-modification materials may change their properties inorder to provide feedback to a user of active stylus 20. As an example,sliders 32 may comprise liquid crystal elastomers that are capable ofchanging their opacity, and thus their display, when subject to anelectric field or change in temperature. By changing the contentdisplayed, sliders 32 may alert the user of information (for example howmuch battery power remains available to active stylus 20). In particularembodiments, one or more sliders 32 at least partially comprisingsurface-modification materials may change their properties to alter orgenerate new input to a touch-sensitive system. Using the example above,a user may select a specific mode or function, such as putting activestylus 20 in a secure operating mode, associated with slider 32 bychanging the display of the liquid crystal elastomer. While the abovedisclosure provides specific examples of sliders comprisingsurface-modification materials providing specific functionality, thisdisclosure contemplates any suitable surface-modification materials onany suitable component of an active stylus providing any suitablefunctionality.

In particular embodiments, one or more textured surfaces 40 at leastpartially comprising surface-modification materials may change theirproperties in order to provide feedback to a user of active stylus 20.As an example, textured surfaces 40 may comprise at least in part ashape-memory polymer, which changes shape or size in response to athermal or electrical input. Altering the shape-memory polymer's size orshape may provide tactile feedback, such as Braille for avisually-impaired user, based on the content displayed on atouch-sensitive device or settings of the device or active stylus 20.Textured surfaces 40 may be arranged in any suitable configuration, suchas an array of posts composed of shape-memory polymers. Individualelements of the configuration, such as individual posts, may have theirsize or shape modified individually, providing for a wide variety oftextures, sizes, and shapes available to textured surfaces 40. Asanother example, textured surfaces 40 may change texture in response tooutput displayed on a device such as roughness of a virtual surface,altitude of particular points in a picture, or changes in any variableembodied by a contour map. The output displayed on the device iscommunicated to active stylus 20, which provides the thermal orelectrical input necessary to make desired change in textured surfaces40. In particular embodiments, one or more textured surfaces 40 at leastpartially comprising surface-modification materials may change theirproperties to change or generate input to a touch-sensitive system. Asan example, textured surface 40 may be non-operable in its non-actuatedconfiguration and operable in its actuated configuration (for example toprevent accidental activation of an associated function such as deletingfiles). While the above disclosure provides specific examples oftextured surfaces comprising surface-modification materials providingspecific functionality, this disclosure contemplates any suitablesurface-modification materials on any suitable component of an activestylus providing any suitable functionality.

In particular embodiments, one or more surface areas 56 at leastpartially comprising surface-modification materials may change theirproperties in order to provide feedback to a user of active stylus 20.As an example, surface area 56 is an electrochromogenic material thatchanges brightness, color, or opacity in response to an electricalcurrent. Different colors or degrees of opacity provide feedback such asan indicator of battery level, security settings, success or failure ofan operation performed, or any other suitable feedback concerning atouch-sensitive system and associated content. While the abovedisclosure provides specific examples of surface-modification materialson a particular surface area providing for specific functionality, thisdisclosure contemplates any suitable surface-modification materials onany suitable component of an active stylus providing any suitablefunctionality.

Herein, reference to a computer-readable non-transitory storage mediumencompasses a semiconductor-based or other integrated circuit (IC)(such, as for example, a field-programmable gate array (FPGA) or anapplication-specific IC (ASIC)), a hard disk (HDD), a hybrid hard drive(HHD), an optical disc, an optical disc drive (ODD), a magneto-opticaldisc, a magneto-optical drive, a floppy disk, a floppy disk drive (FDD),magnetic tape, a holographic storage medium, a solid-state drive (SSD),a RAM-drive, a SECURE DIGITAL card, a SECURE DIGITAL drive, or anothersuitable computer-readable non-transitory storage medium or acombination of two or more of these, where appropriate. Acomputer-readable non-transitory storage medium may be volatile,non-volatile, or a combination of volatile and non-volatile, whereappropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Moreover,reference in the appended claims to an apparatus or system or acomponent of an apparatus or system being adapted to, arranged to,capable of, configured to, enabled to, operable to, or operative toperform a particular function encompasses that apparatus, system,component, whether or not it or that particular function is activated,turned on, or unlocked, as long as that apparatus, system, or componentis so adapted, arranged, capable, configured, enabled, operable, oroperative.

What is claimed is:
 1. A stylus comprising: one or more electrodes andone or more first non-transitory computer-readable storage mediaembodying logic for transmitting signals wirelessly to a device througha touch sensor of the device; and an electronic circuit operable toprovide an input altering a property of one or more materials, the oneor more materials existing on one or more of: at least part of a tip ofthe stylus; or at least part of a surface area of the stylus.
 2. Thestylus of claim 1, wherein the property comprises one or more of: shape;size; hardness; effective coefficient of friction; brightness; color;viscosity; texture; temperature; or opacity.
 3. The stylus of claim 1,wherein the input comprises one or more of: an electromagnetic field; anelectric current; a temperature; a radio frequency; or a pH level. 4.The stylus of claim 1, wherein the one or more materials comprise one ormore of: a shape-memory alloy; a shape-memory polymer; an electronic orionic electroactive polymer; a magnetocaloric material; a thermoelectricmaterial; a pH-sensitive material; a temperature-responsive material; apiezoelectric; a halochromic material; a chromogenic material; or aphotomechanical material.
 5. The stylus of claim 1, wherein the at leastpart of the surface area of the stylus comprises one or more of: abutton; a slider; or a textured surface.
 6. The stylus of claim 1,wherein the electronic circuit provides the input based on one or moreof: a signal initiated by a user of the stylus; or contents of one ormore second non-transitory computer-readable storage media.
 7. Thestylus of claim 6, wherein the contents of the one or more secondnon-transitory computer-readable storage media are determined by one ormore of: the user of the stylus; software associated with the stylus orthe device; or preset prior to any user's initial use of the stylus. 8.One or more first computer-readable non-transitory storage mediaembodying first logic operable when executed to: initiate provision ofan input altering a property of one or more materials, the one or morematerials existing on one or more of: at least part of a tip of thestylus; or at least part of a surface area of the stylus, the styluscomprising one or more electrodes and one or more secondcomputer-readable non-transitory storage media embodying second logicfor transmitting signals wirelessly to a device through a touch sensorof the device.
 9. The media of claim 8, wherein the property comprisesone or more of: shape; size; hardness; effective coefficient offriction; brightness; color; viscosity; texture; temperature; oropacity.
 10. The media of claim 8, wherein the input comprises one ormore of: an electromagnetic field; an electric current; a temperature; aradio frequency; or a pH level.
 11. The media of claim 8, wherein theone or more materials comprise one or more of: a shape-memory alloy; ashape-memory polymer; an electronic or ionic electroactive polymer; amagnetocaloric material; a thermoelectric material; a pH-sensitivematerial; a temperature-responsive material; a piezoelectric; ahalochromic material; a chromogenic material; or a photomechanicalmaterial.
 12. The media of claim 8, wherein the at least part of thesurface area of the stylus comprises one or more of: a button; a slider;or a textured surface.
 13. The media of claim 8, wherein the first logicinitiates provision of the input based on one or more of: a signalgenerated by a user of the stylus; or contents of one or more thirdnon-transitory computer-readable storage media.
 14. The media of claim13, wherein the contents of the one or more third non-transitorycomputer-readable storage media are determined by one or more of: theuser of the stylus; software associated with the stylus or the device;or preset prior to any user's initial use of the stylus.
 15. A methodcomprising: providing from a stylus an input, the input altering aproperty of one or more materials and the one or more materials existingon one or more of: at least part of a stylus tip; or at least part of asurface area of the stylus, the stylus comprising one or more electrodesand one or more first computer-readable non-transitory storage mediaembodying first logic for transmitting signals wirelessly to a devicethrough a touch sensor of the device.
 16. The method of claim 15,wherein the property comprises one or more of: shape; size; hardness;effective coefficient of friction; brightness; color; viscosity;texture; temperature; or opacity.
 17. The method of claim 15, whereinthe input comprises one or more of: an electromagnetic field; anelectric current; a temperature; a radio frequency; or a pH level. 18.The method of claim 15, wherein the one or more materials comprise oneor more of: a shape-memory alloy; a shape-memory polymer; an electronicor ionic electroactive polymer; a magnetocaloric material; athermoelectric material; a pH-sensitive material; atemperature-responsive material; a piezoelectric; a halochromicmaterial; a chromogenic material; or a photomechanical material.
 19. Themethod of claim 15, wherein the at least part of a surface areacomprises one or more of: a button; a slider; or a textured surface. 20.The method of claim 15, wherein the input is provided based on one ormore of: a signal generated by a user of the stylus; or contents of oneor more second non-transitory computer-readable storage media.